980ti can only squeeze in at £1000 so if you want it nice looking too i would just settle for a 970 for the time being. I would say a 980 but the price performance is not great so only get a 980 if you feel its justified. Or even buy an extreme overclocked 970 which will pull the same as a 980.
TL;DR 980Ti overkill anyway, 970 best option unless 980 is preferred